Investigators have pinpointed the likely source that sickened almost 300 customers at a Holland Township restaurant.

After reviewing food histories of diners who ate at Wild Chef Japanese Steakhouse Grill and Bar, 2864 West Shore Drive, from March 28 to April 1, investigators determined the likely norovirus source as a sauce — either white sauce, yum-yum Sauce or shrimp sauce.

Customers who fell ill experienced nausea, abdominal cramps, diarrhea, vomiting and other symptoms. Wild Chef owner Jay Zheng said in a statement that the restaurant abides by food safety regulations and works “cooperatively with the health department to ensure the best quality food and service” to its customers. He said they have done so for nearly 10 years.

“We learned from this experience and have emerged better, and more aware, for the benefit of our patrons,” Zheng said.

The Ottawa County Department of Public Health became aware of the situation in early April after a customer emailed them with a concern after becoming ill after eating at the establishment. Health department epidemiologist Marcia Knol said health officials visited the restaurant after the first complaint, but they didn’t notice any obvious breakdowns in procedures.